SMART ENTRY AND START SYSTEM (for Start Function) Power Source Mode does not Change to ON (IG)

DESCRIPTION

If the engine switch is pressed with the electrical key transmitter sub-assembly in the cabin, the certification ECU (smart key ECU assembly) receives a signal and changes the power source mode.

Tech Tips

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

WIRING DIAGRAM

INSPECTION PROCEDURE

Note

When using the intelligent tester with the engine switch off, perform either of the following: 1) Turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the intelligent tester and vehicle begins, or 2) connect the intelligent tester to the vehicle, select the vehicle type under manual mode, and then enter the following menus: Body / Entry & Start / DTC.
The smart entry and start system (for Start Function) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting Click here. Troubleshoot the smart entry and start system (for Start Function) after confirming that the communication systems are functioning properly.
Make sure that no DTCs are output. If any DTCs are output, proceed to the Diagnostic Trouble Code Chart Click here.
If the smart entry and start system is disabled through the customize function, enable the system before performing troubleshooting Click here.
Before replacing the certification ECU (smart key ECU assembly), refer to the smart entry and start system (for Start Function) precaution Click here.
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
After completing repairs, confirm that the problem does not occur.

Tech Tips

Related Data List and Active Test Items
Problem Symptom	Data List Item	Active Test Item
Power source mode does not change to on (IG) but does change to on (ACC)	Power Source Control Power Supply Condition IG1 Relay Monitor (Inside) IG2 Relay Monitor (Inside) IG1 Relay Monitor (Outside) IG2 Relay Monitor (Outside) IG1 Circuit IG2 Circuit	-

PROCEDURE

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INTEGRATION RELAY)

Disconnect the A43 connector from the certification ECU (smart key ECU assembly).
Disconnect the 1C and 1E connectors from the No. 2 integration relay.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
A43-9 (IG2D) - 1C-8	Always	Below 1 Ω
1E-2 - Body ground	Always	Below 1 Ω
A43-9 (IG2D) or 1C-8 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT NO. 1 INTEGRATION RELAY (IG2 RELAY)

Text in Illustration

*a
Component without harness connected

(No. 1 Integration Relay)

Remove the No. 1 integration relay (for 2AR-FE) Click here.
Remove the No. 1 integration relay (for 2GR-FE) Click here.

Text in Illustration
*a	Component without harness connected (No. 1 Integration Relay)

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
1A-1 - 1D-3	Battery voltage not applied to terminals 1C-8 and 1E-2	10 kΩ or higher
1A-1 - 1D-3	Battery voltage applied to terminals 1C-8 and 1E-2	Below 1 Ω

Result

Result	Proceed to
OK	A
NG (for 2AR-FE)	B
NG (for 2GR-FE)	C

REPLACE NO. 1 INTEGRATION RELAY Click here

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

Disconnect the I78 connector from the certification ECU (smart key ECU assembly).
Disconnect the 3A connector from the instrument panel junction block assembly.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
I78-6 (IG1D) - 3A-27	Always	Below 1 Ω
3B-7 - Body ground	Always	Below 1 Ω
I78-6 (IG1D) and 3A-27 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1, IG1 NO. 2, IG1 NO. 3 AND IG1 NO. 4 RELAY)

Remove the instrument panel junction block assembly Click here.
Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly Click here.

Measure the resistance according to the value(s) in the table below.

Text in Illustration
*A	for LHD	*B	for RHD
*a	Component without harness connected (Instrument Panel Junction Block Assembly)	-	-

Standard Resistance

for LHD
Tester Connection	Condition	Specified Condition
3E-1 - 3D-33 (IG1 No. 1 relay) 3E-1 - 3D-36 (IG1 No. 2 relay) 3E-1 - 3C-4 (IG1 No. 3 relay) 3E-1 - 3C-14 (IG1 No. 4 relay)	Battery voltage not applied to terminals 3A-27 and 3B-7	10 kΩ or higher
	Battery voltage applied to terminals 3A-27 and 3B-7	Below 1 Ω

for RHD
Tester Connection	Condition	Specified Condition
3F-1 - 3D-33 (IG1 No. 1 relay) 3F-1 - 3D-36 (IG1 No. 2 relay) 3F-1 - 3C-4 (IG1 No. 3 relay) 3F-1 - 3C-14 (IG1 No. 4 relay)	Battery voltage not applied to terminals 3A-27 and 3B-7	10 kΩ or higher
	Battery voltage applied to terminals 3A-27 and 3B-7	Below 1 Ω

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Measure the voltage according to the value(s) in the table below.

Text in Illustration
*a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))	-	-

Standard Voltage

Tester Connection	Condition	Specified Condition
A43-9 (IG2D) - Body ground	Engine switch on (ACC) → Engine switch on (IG)	1 V or less → 9 V or higher
I78-6 (IG1D) - Body ground	Engine switch on (ACC) → Engine switch on (IG)	1 V or less → 9 V or higher

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

CHECK RELAY CONTACT SIDE CIRCUIT Click here